Here we are a little under 48 hours away from our next Winter Storm and model guidance is still all over the place across Pennsylvania for who receives what and how much. But, as weather forecasters, this is one of the many challenges we face quite often and we will give you the forecast the way we see it.

With that being said, we are confident that overrunning snow showers will overspread the state during the day Sunday which is well represented by latest NAM model valid 7 AM Sunday Morning:

As the day progresses Sunday, it is quite possible that snow stops at times and then picks back up again through the Evening hours. By the time we reach later into Sunday Evening, steadier snows will develop from Southwest to Northeast. It is quite likely almost all the state at least starts off as a brief period of snow Sunday Night. How long areas hang onto the snowfall is where it differs greatly throughout the state. General rule of thumb for this system, the further North you are, the better chance to see a longer duration of snow.

The Canadian Model shows the steadier snows overspreading the state Sunday Night, this future radar image is valid at 1 AM Monday Morning:

As the system progresses, it is probable many areas do end as a plain rainfall.

The GFS is much warmer than the CMC. While the European model is right in between the GFS and CMC in terms of how warm/cold it is. The differences in these models is their handling of the High Pressure over the Northeast. GFS kicks it out much quicker than the rest of the models, allowing for a warm solution, while the rest keep it closer to our area, preventing a mainly rain event. These are details we will iron out over the next day or two.

For now, this is how we see it playing out Sunday into Monday:

WINTER STORM MAP FORECAST

Area A: 4 to 7 inches of snowfall. Best chance to see all snow but a changeover to rain at the very end of the event is possible.

Area B: 2 to 4 inches of snowfall, with 0.01 to .05 inches of ice accretion. A change to rain at the end is possible.

Area C: 1 to 2 inches of snowfall, with .01 to 0.05 inches of ice accretion. The precipitation will end as rain.

Area D: Area we are most concerned with ice potential. 1 to 2 inches of snowfall, followed by 0.05 to .15 inches of ice accretion. The Precipitation will end as rain.

Area E: Up to an inch of snow before changing to rainfall.

Both Sunday Evening and Monday Morning commutes will be impacted by this storm! Give yourself extra time to wherever you may be traveling during that time.Our confidence is only at a medium level right now, so please be sure to click here to stay tuned for future updates by liking us on Facebook>>>>PA Weather Action on Facebook! Don’t forget to share the details with your friends and family about the upcoming Winter Storm Sunday into Monday below. Stay safe! Next updated map will be posted Tomorrow Evening.

With temperatures plunging tonight, wind chills in the teens are likely Friday Morning. Well below average temperatures will continue into the weekend with highs only in the 20s and 30s expected both Saturday and Sunday. At the same time, a low pressure system will develop in the Great Plains, moving east through the weekend. There continues to be some model disagreement. With that said, one solution appears to be emerging.

Impacts across the state will undoubted vary. However, much more of the state will get in on the winter weather action. This time, we don’t just a few hours of sleet. Some areas could see over a half foot of snow, while others will encounter much less. Snowfall amounts remain unknown at this time.

MAP FORECAST FOR WINTER STORM SUNDAY INTO MONDAY

MODERATE: This area can expect snowfall for the majority of the storm, however the event will likely end with a few hours of rain. Travel disruptions likely Monday Morning. Moderate snowfall accumulation possible. A slight glaze of ice cannot be ruled out as upper levels warm but surface temperatures hover around freezing Late Monday Morning.

MINIMAL: This area can expect snowfall for a few hours Sunday Night before changing over to all rain Monday Morning. Minimal snowfall accumulation possible. Slight travel is possible early Monday Morning.

As the title indicates, a significant multi-day lake effect snow event is likely in Northwest PA. Snow will begin Thursday, intensifying Friday. By Saturday lake effect banding will begin to diminish.

Most persistent lake effect snow bands will likely be in Erie, Crawford and Warren Counties. Snowfall amounts could reach two feet in areas shaded in red on our forecast map below. Locations such as Erie will receive around 7-10″ total, as will Warren. Meadville will see 8-12″ of snow.

Sunday will feature precipitation, but there is a great deal of disagreement in the models. There is a good chance of wintry precipitation, but that’s about all we know at this point. Even the severity of the event remains largely up in the air.

A light wintry mix pushed through the state Sunday Night, dropping anything from plain rain in Pittsburgh and Philadelphia to sleet across much of the Lower Susquehanna Valley and Lehigh Valley along with up to two inches of snow in higher elevations of the Central and Western PA.

Now, our focus shifts to another wintry mix event expected Tuesday Evening through Wednesday Morning. Both the European Model and the American Model had been very consistent in showing very different solutions up until last night. However a consensus throughout the models has developed today. Overall, the GFS (American Model) will take the prize as the usually persistent and top notch European Model has folded to the GFS Solution.

This now means the dominant precipitation type in Southcentral and Southeast Pennsylvania will be rain. As originally expected, Southwestern Pennsylvania will see rain as well. As you work your way up into the Pocono Region and west into the Northern PA Mountains, you will run into some wintry weather. Here is our Map Forecast.

TUESDAY PM – WEDNESDAY AM WINTRY MIX MAP FORECAST

Area A – Snow likely Tuesday Night ending with a short period of rain Wednesday Morning. Snowfall accumulation of 2-4″.

Area B – Snow likely Tuesday Night before changing to sleet, then rain by Wednesday Morning. Snowfall accumulation of 1-2″.

Area C – A few hours of snow are likely to begin the event before changing over to rain by Early Wednesday Morning. Snowfall accumulation of up to 1″. A coating of ice is also possible in the Laurel Highlands.

Area D – A very short period of sleet or snow is likely to begin the event, followed by a change to rain. A coating of snow is possible but will quickly be melted away. A coating of ice is also possible in the Laurel Highlands.

Area E – Sleet or snow may mix in for an extremely short period in the beginning of the event, then rain.

All other areas can expect an all rain event.

For our Final Call regarding this Wintry Mix and updates on the many storms to come this Winter make sure you have us liked on Facebook by clicking here>>>PA Weather Action on Facebook!

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As for the bigger storm potential, we are tracking a Winter Storm set to begin Tuesday Evening and lasting through Wednesday Morning. A low pressure system will develop in the South and track its way Northward before transferring its energy into a coastal low. Over the last 36-48 hours, guidance has been steadily trending colder and colder for this system. While this still won’t be an all snow event for most of us, this will lead to a longer duration of snow versus rain for many locations.

For a visual on this, below is the Canadian Model valid 7 PM Tuesday Evening.

The further North you are in PA and the higher your elevation is will increase your chances of receiving accumulating snowfall. Many low elevated valleys will receive a slushy mix or just a cold rain.

It is projected as this storm wraps up and the precipitation weakens, most locations end in the form of light rain.

Timing: Tuesday Evening into Wednesday Morning

MAP FORECAST FOR WINTER STORM TUESDAY INTO WEDNESDAY

Area A: 4 to 6 inches of heavy wet snow is possible, ending as a brief period of drizzle. Isolated power outages would be possible in these areas as the snow would weigh on power lines and tree limbs.

Area B: 2 to 4 inches of wet snow is possible, ending as a period of light rain.

Area C: 1 to 2 inches of wet snow is possible before changing to a period of rain.

Area D: Up to 1 inch of wet snow is possible before changing to rain.

Area E: Up to a coating of wet snow is possible before changing to rain.

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Two separate winter weather events are likely in the coming days, before temperatures drop Friday (Dec 9th). There is a good chance that a winter storm with widespread impacts will take place sometime between December 9th and December 17th. However as mentioned we have two events incoming just in the next several days.

The first event arrives Sunday Evening, leaving Monday Morning. A clipper-like system will move through the region resulting in light rain and snow.

SUNDAY PM – MONDAY AM CLIPPER MAP FORECAST

Area A: Light snow will move in Sunday Evening from west to east, exiting from west to east as well Monday Morning. About 1-2″ of snowfall accumulation expected, with up to 3″ above 2,000′ elevation. If not salted, roadways may be snow coated or covered.

Area B: Light rain at the onset of precipitation will Sunday Evening will change to snow after 10 PM, lasting through Monday Morning when snowfall will move out from west to east. A coating to an inch of snowfall accumulation is expected with scattered amounts of up to 2″ above 2,000′ elevation.

Area C: Light rain at the onset of precipitation will lead to a change-over to snow late Sunday Evening into Early Monday Morning before changing back over to rain. A coating of snowfall is possible but will be melted by rainfall. Areas above 1,800′ may receive up to an inch of snowfall.

The second event arrives Tuesday, lasting into Wednesday. Here is the current prediction for that event.

TUESDAY – WEDNESDAY WINTRY MIX MAP FORECAST

Area A: Snow will move in Tuesday Evening, continuing through the night and into Wednesday Morning. A change-over to rain is possible at the end of the event Wednesday Afternoon. However by then only light precipitation will remain. Moderate snowfall accumulation possible.

Area B: Snow will move in Tuesday Evening, lasting into the pre-dawn hours of Wednesday before changing over to rain. Light to moderate snowfall accumulation possible.

Area C: Precipitation will enter the area Tuesday Evening likely as snow. Snow will persist for several hours before changing over to rain a few hours before sunrise Wednesday. Light snowfall accumulation possible.

What we thought originally was going to be a sheared out system for Monday, now looks like it will be a snow maker for some, and a rain/snow mix for others beginning late Sunday Night into Monday. Then behind that system, we are tracking a larger storm as we mentioned yesterday, that could produce a more significant amount of rain and/or snow for many areas.

First off below is the latest GFS valid 1 AM Monday Morning:

Temperatures will be very marginal, so for lower elevations, this might just be a cold rain for you. But areas that do receive snow, could see up to a couple inches mainly in grassy surfaces.

Here is our First Call for Sunday Night into Monday:

Area A: 1-2 inches of snowfall is expected.

Area B: A coating to 1 inch of snowfall is expected, possibly mixing with some rain showers.

Area C: A snow/rain mix is expected. A slushy coating is possible.

Then our eyes rapidly turn to the Tuesday-Wednesday time-frame. A low pressure system will likely cut to our West, through the Ohio Valley, then will transfer its energy into a coastal low. How quickly it transfers its energy into the coastal low will determine how much wintry precipitation our state receives. The earlier the better for those rooting for snow.

Here’s a look at the latest GFS valid 7 PM Tuesday Night:

This is a much warmer solution than other guidance as the primary low cuts over the PA/OH border. If this were the case we would see a mainly rain event. But, the European and Canadian guidance is much colder with the system and actually brings several inches of snowfall across much of Central PA. Lower amounts further East and West.

Based on latest trends, we will likely have to have a first call map for the Tuesday/Wednesday system posted by Tomorrow Evening, as well as a second call for Sunday Night/Monday. For the latest, follow our Facebook page by clicking here>>>>PA Weather Action on Facebook!

Last December was a December to remember in terms of how warm it was, this December will be the complete opposite, as we had expected since the release of our Winter Outlook back on November 1st. And now over the last few days, model guidance is beginning to catch on, and beginning to catch on in a big way.

This post will just be focused on the first 10 days of December. If you haven’t already, click here to check out our December forecast>>>December 2016 Forecast

After some much needed rainfall the last couple days, our weather is back to normal and even blustery. Northwest winds will pick up Friday Night into Saturday, enough so that Lake Effect Rain and Snow showers are possible for the North and West half of the state during this time-frame.

Accumulations should be rather limited, but a coating to an inch is not out of the question for the Laurel Highlands and also for far Northern PA.

The next opportunity for some snow will come from a weak wave that will likely shear apart as it reaches the state on Monday. IF it holds together, this will bring light snows to just about all of PA. But right now, it looks like this system will shear apart before it reaches the state. We will keep an eye on it, but it does not look like it will be a big deal.

What does have the potential of being a bigger deal, is a storm system that will be developing from the South and tracking West of the Appalachians before transferring its energy to the Coast during the Tuesday-Wednesday time period. We will use the GFS to breakdown this potential storm below:

There are numerous factors involved with this system…1. How far North does the primary low travel? 2. When does it transfer its energy to the coast? 3. Where will the high pressure be placed? 4. How strong will the high pressure be?

Many questions to be answered over the next coming days. For now, the GFS takes the primary low and cuts it will into Northern Ohio and eventually into Southern Canada before completely losing its energy to the coastal that forms. Because this system is to our West, with a counter-clockwise flow, this will allow for warmer air to invade from the south allowing for much of this precipitation to be in the form of rain for many of us. The transfer to the coast does not happen until it is off of the Virginia Coastline on the GFS. This is a good 100 miles North of where the European has it. Although we are unable to show you, the Euro is very similar to the GFS, but colder, allowing for more wintry precipitation to fall.

If you are rooting for a more Wintry solution, the primary low needs to die further South, Kentucky would be ideal, but if it transferred its energy before it reaches the Northern half of Ohio, then that is fine as well. The coastal low that forms, must not form any further than what the GFS shows here. The further South it forms, the better. Lastly, if the High Pressure is placed a little more to the West across Southern Canada, rather than Maine and is a little stronger than what is currently modeled, this will help prevent our primary low from cutting far North which will allow for increased odds in a Wintry solution.

Even with the GFS’s solution here, because of the High Pressure placed up near Maine, this allows for at least some frozen precipitation to start before switching over to plain rain. As of now, areas North of I-80 and the Laurel Highlands will be favored for a more wintry event during the Tuesday-Wednesday time period before ending as rain. This does have time to trend colder..or warmer. We will see how it plays out. The potential does exist for someone to see a significant winter event if everything aligns correctly.

What is almost a certainty is that it is going to get very cold. 10 to 20 degrees colder than normal will be a common theme for at least several days after the 8th. Take a look at projected high temperatures for December 9th: GFS does overdo the cold in the long range at times, however there is an overwhelming consensus among guidance. Verbatim, this is showing next Friday’s high temperatures to be in the teens and 20s across PA, with the 32 degree line well to our South and East. Extremely impressive for this time of year and a good 10-20+ degrees colder than normal. Teens and 20s might be a bit too aggressive in our opinion, but 20s and 30s for high temperatures is looking likely for at least the December 8th-10th timeperiod.

We will have many more updates as we track three upcoming snow chances (Friday Night into Saturday, low impact), (Monday, low to no impact), (Tuesday into Wednesday, potentially a bigger impact) so make sure you click here to follow our Facebook page to receive these updates>>>PA Weather Action on Facebook!

December is nearly upon us, meaning winter weather is just about here. However if this December is anything like December 2015, every other morning will be foggy and snow will be nonexistent. Those of you who read our Official Winter Outlook know that will not be the case this December.

In fact, there are already two periods of interest in the first 10 days of December. The first, less promising period is December 4th/5th. The next period that looks fairly interesting is December 9th/10th. By then the cold will be more established and numerous models have a storm system on the East Coast during that time-frame.

By Mid-December, the cold air will be locked in and there will be increased winter storm chances. Late December around Christmas and New Years also has a good chance of being on the cold side, with an active pattern as well.

Based off what you’ve just read, you can probably guess what’s coming next. Below is our Map Forecasts, featuring temperatures and snowfall compared to normal.

Currently as of 3 PM the cold front is centered right over Central PA splitting PA in half of two different seasons. Spring in the East and Winter in the West! The cold front will continue to push East, packing a very cold punch along with rain showers changing to snow showers the further West you go.

Area A – 6 to 10 inches of snowfall, with isolated amounts up to a foot possible. Blizzard like conditions will be felt at times with winds gusting over 40 mph.

Area B – 4 to 6 inches of snowfall is expected. Blizzard like conditions are possible due to winds gusting over 40 mph.

Area C – 2 to 4 inches of snowfall is expected. Whiteout conditions are possible at times due to winds gusting over 40 mph.

Hope you all are enjoying the warm weather while it lasts because we are narrowing in on the details of this season’s first widespread snowfall beginning Tomorrow Afternoon and lasting through Monday.

Do not let Tomorrow’s early on temperatures fool you, as it will be very warm to start your day off on your Saturday. Here are the projected temperatures for 2 PM Saturday Afternoon:

A very strong cold front is splitting the state about in half. Temperatures ahead of this front will likely reach the mid to upper 60s in many locations. But looking out behind the front, you can see the cold temperatures that trail this front.

As we take the Hi-Res NAM model out to 7 PM Saturday Evening, the cold front has now just about made it through the state. Verbatim it is located right around the PA/NJ border. . You can see the rapid crash in temperatures across the Eastern half of the state.

The main thing to take away from this is, it will be a warm start Tomorrow. And many places will start off as rain. But once the cold front pushes through, expect a rapid drop in temperatures and winds to pick up tremendously, with snow flying in the air especially the farther North and West you go.

Below is our second call. The only changes that were made, was to upgrade some areas in NW PA and downgrade other areas slightly. For the most part, very similar to our first call.

After what will be a warm Friday and Saturday, it will be hard to believe our first widespread snow event of the year will arrive late Saturday Evening and continue through Sunday and even into some of your Monday especially for Northern areas.

A cold front will sleep through the area during the day Saturday, dropping temperatures from 50s and 60s in the early part of the day, to 30s and 40s by the evening hours. From here, it is expected that a low pressure system develops along the front once it reaches the coastline, which will then allow for winds to pick up from the North and Northwest. Combination of gusty winds and warm lakes, will result in our first widespread snow showers and Lake Effect snows.

Below is the latest NAM model valid Sunday Afternoon:
Timing: It will start in the late afternoon hours Saturday and will continue through Sunday and into Monday for Northern parts of PA.

Areas in the 4-7″+ range have the potential of receiving more if persistent heavy lake effect snow bands set up. Areas in the light blue can just expect some possible snow showers, with little to no accumulation.

Most areas will only receive accumulation on grassy surfaces with the exception of areas in the red and pink where if the snow is coming down hard enough, it will have no problem sticking to paved surfaces.

Our first widespread snow event of the season is likely Sunday into Monday across much of Pennsylvania. Models are beginning to align, raising our overall forecast confidence. There is the potential for significant snowfall in parts of the state.

Breakdown: A low pressure system will move through the Upper Great Lakes late this week. A cold front will be partnered with this system, sweeping through the region Saturday Evening into Sunday Morning. Precipitation will switch from rain to snow from west to east throughout Western and Central Pennsylvania. However, the majority of the anticipated snowfall will be lake effect as strong northwest winds blow heavy snow showers off Lake Erie.

Temperatures will drop 20-30 degrees Saturday Evening as a result of this cold front. Wind gusts over 30 MPH are also expected as the front passes through.

MAP FORECAST

Area A – Significant snowfall accumulation possible. Snow will begin Saturday Night, continuing through the day on Sunday, lasting all the way until Monday Evening. Areas in strongest and most persistent lake effect snow bands may experience near white-out conditions and 6-12″ of snow.

Area C – Light snowfall accumulation possible. Snow will begin Saturday Night into Sunday Morning. It will be off-and-on through the day Sunday before wrapping up Sunday Night. About 1-3″ of snow is possible.

Area D – Snow showers possible Saturday Night into Sunday Afternoon, wrapping up by evening. Flurries to a scattered coating is possible.

We are currently tracking our first potential Winter Storm of the season, that will arrive late Saturday Evening and will last through Sunday. The potential storm system is roughly 100 hours away from impact and there is big time disagreement with our current guidance.

Breakdown: A low pressure system will be cutting through the Great Lakes region late this week and will have a trailing cold front along with it. The cold front is our main focus. As we head into the day Saturday, the cold front will cross the state from West to East. The cold front will bring with it rain showers to start, but these rain showers will change to snow showers as temperatures will rapidly drop.

GFS projected high temps for Saturday valid 2 PM:

You can clearly see the cold front splitting PA in half. And yes, it’s possible for areas to be in the upper 50s, to even 60s in the afternoon Saturday and have snow falling by late Saturday Night into Early Sunday Morning.

We will skip to next frame here valid 8 PM Saturday Evening after the Cold Front has passed through:

15 to 30 degree temperature drop across Eastern PA. More importantly, the Western half of PA stayed relatively cold in both images, leading to increased odds of receiving some accumulating snowfall.

The major difference between the models right now is whether a coastal storm forms off the Jersey Coast as the front approaches the coastline. The Euro and Canadian develop this rapidly, especially the Euro, which helps produce a significant snowfall for much of the state Saturday Night into Sunday. The GFS on the other hand, is much less aggressive and does not develop the coastal low until it is well North of our area, resulting in wraparound lake effect snows for the Western part of the state, but nothing significant.

How much snow are the models printing out? GFS, is the least aggressive with a couple inches of snowfall for the Northwest part of the State. The Canadian model is the middle ground right now, with a widespread 3-6″+ snowfall, with the exception of Southeastern PA. The European, the most aggressive model, has a widespread 8-12″+ for Central and Western areas of PA. While Eastern PA only receives upwards of an inch or two.

The European Model seems a little too aggressive in our opinion, but it is not impossible. Taking a blend of all three models we come up with this map below: No amounts just yet, we will wait until we are within 3 days before we start forecasting numbers.

Again the timing of this system looks be Saturday Evening through Sunday.

Because of the major differences in the model guidance it is important to make sure you have us “liked” on Facebook for the latest by clicking here>>>PA Weather Action on Facebook!

**All areas will begin as rain before changing to snow.**

Area A: Regardless of whether a coastal low develops or not, this area has the best chance of receiving accumulating snowfall. Whether it be a coating, or more than 10 inches, it is too early to tell.

Area B: Accumulating snowfall is possible in this area. Depending how fast temperatures drop after the cold front passes through, will be a big determining factor whether the snow will have the opportunity to stick. However, if it snows hard enough, temperatures won’t be an issue. Again, too early to tell exact totals, if any.

Area C: Some snowfall is possible, but likely will not accumulate.

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Last Thursday it was announced by NOAA that a Weak La Niña had formed in the Equatorial Pacific. Although it will remain fairly weak, its impacts could be felt here in Pennsylvania where we typically see many mixed precipitation events.

A La Niña raises the chance of an active northern stream. As a result, this season we will have an increased chance of experiencing storms originating in the Plains or Canada. There will likely be less than normal coastal storms. Unfortunately for those looking for a blizzard repeat, this means the chance of strong Nor’ Easters is low this winter.

As mentioned, many of the storms we encounter will form in the Central Plains and Canada. Since there is no major body of water in either area, this season will likely be full of small to moderate events similar to 2013-14. Below is a graphic to give you a better idea of northern stream storms.

Generally areas about 100 miles north of the low pressure see mainly snow. However, above the graphic shows low pressure tracks in the DC-Baltimore Area. This all depends on how deep the cold air is and the placement of a high pressure in Ontario.

If systems often track over the DC-Baltimore Area, Southern Pennsylvania will see many mixing events while Northern PA is on the snowier side. We think there is a good chance this happens several times during the upcoming season.

Another system that will occur often this season is the Alberta Clipper. These systems are almost often partnered with cold air, resulting in a frozen precipitation type on either side of the low pressure.

Below is a graphic of La Niña’s Potential Impacts On Pennsylvania this upcoming winter.

The northern third of the state is likely to see mainly snow events, the middle third could see mixing every so often but primarily snow events, and the southern third of PA will see mixed bags fairly often.

Don’t worry snow lovers, this does not impact our forecast snow totals for this Winter. Everything still remains on track.